Thrust Force Analyses in Drilling FRP Composites

Abstract

Whenever fiber-reinforced polymer (FRP) composites are drilled to produce a hole, it is necessary to obtain the desired dimensional requirements with minimal surface and sub-surface damage. A number of complications arise in this process, such as multiphase laminated materials (hard reinforced fibers within soft polymer matrix) and complex cutting edges of the drill bit. According to existing research, changes in the drilling parameters’ setting and tool geometry play a critical role in influencing the thrust force and size of delamination zone. Thus, the workpiece’s delamination responses can be minimised by identifying proper drilling parameters and tool geometry to reduce the effect of thrust force on uncut layers. Analytical as well as experimental investigations have explored the thrust force and delamination behaviour during composite drilling, to compute the critical thrust force at the onset of delamination during drilling. All studies cited in this review indicate that delamination damage can be avoided if the applied thrust force is lower than the critical thrust force value. A good agreement between the estimated critical thrust force and the measured thrust force was evident in certain studies. Considering this, the critical thrust force value can be a reliable benchmark or reference for industrial practice in reducing delamination damage for better assembly performance of the drilled FRP composites. Lastly, a general review of new approaches to reduce the drilling thrust force for reaching delamination free drilling for FRP composite laminates has been attempted.KeywordsCritical thrust forceDelaminationDrillingFRP compositesThrust force